Pneumatic jack



.May 22, 1923.

W. F. KELLY PNEUMATIC JACK Filed July 5, 1921 2 Sheets-Sheet l WIT/VESSES May 22, 1923.

W. F. KELLY PNEUMATIC JACK Filed July 5, 1921 2 Sheets-Sheet 2 Flai W/T/VESSES Patented May 22, 1923i. l

UNHTE@ @STATES instan raient ernten.

WILLIAM F. KELLY, or en'EnNwoon, MISSISSIPPI.

-v PNEUMATIC JACK.

Application led Ju1y'5, 1921. Serial No. 482,442.

To all whom z'timag/ concern l Be it known .that I, WILLIAM F. KELLY, a

citizen of the United States, and a resident One of the principal objects "of the inven-V- tion is to provide an improved jack having telescoping sections which may be extended under the action of compressed air, to exert a lifting force for various purposes, such for instance, as lifting the axles of automobiles, etc.

Another Objectis toK provide aconstruction whereby the air may quickly and readily be dispelled from the jack to allow the collapse of the latter into normally inoperative position.

Still another object is toprovide an improved automatically operating means for holding the head of the jack in raised position underneath the load and against'collapsing movement so long as the load is supported, this/means operating automatically to allow a lowering movement of the head when the load is relieved. l v.

A further object is" to provide an imi proved jack of the class described which will be relatively simple, durable and efficient in' operation, and inexpensive to manufacture and maintain.

With "these and other objects in view which will become apparent as the descriptionproceeds, the invention resides in the construction, combination and` arrangement of parts hereinafter more fully described -cord'ing'r to my invention.

and claimed and illustrated in the accompanying drawings' in which like characters of reference indicate like parts .throughout Vthe several igures, and in which:

Figure 1 represents. a ivertical sectional view taken through a ]ack constructed ac- Figures 2, 3and 4 represent sectional views taken through the valve for controlling the admission of air to and its exhaust i from the jack. 'showing the latter in various positions,

Figure 5 represents a sectional view of the automatic valve showing the same in its initial or lowered position,

Figure 6 represents a similar view showing the valve 1n raised position,

Figure 7 represents a horizontal sectional view taken through the jack on a planeindicatedby the line 7-7 of, Figure 1, the

view being partially shown in elevation,

Figures, 9, and 10 represent fragmentary elevational views of the rack member and the controlling means for the latter, lshowing the'controlling means in various.

positions.

'In carrying out my invention, I provide i an outer cylinder 5, closed atI its lower end as vat 6 and provided at its upper end with a threaded closure 7 having a downwardly extending annular guide 'flange 8, through which the inner cylinder 9 slidably extends. At its lower end the inner cylinder is threaded into a piston 10 provided with a spaced .washer 11 secured tothe piston by tween. The washer snugly fits theinterior `of the cylinder 5, and provides for effecting of the cylinder 9 and provides an air-tight connection between the piston and the cylinder walls. The upper end, of the rack 15 carries a detachable head 18 suitably formed, and adapted to be raised into engagement with the work when the jack is placed in operation. y

It may here be noted that in the operation ofthe jack, the rack 15 is raised with remeans of screws or other suitable means 12,v holding a leather cup washer 11 therebespect to` the inner cylinder 9, within which,

when e jack is in inoperative position,the rack islcontained, and after the rack has been moved upwardly to thelimit of its movement. the inner, cylinder 9 moves upwardly with respect to the outer cylinder 5. Bleed holes 19 in the closure 7 of the outer cylinder allow of atmospheric pressureto be lmaintained at all-times and above the piston- 10, andthe openingsin the closure 13 and partition 14 of the inner cylinder allows of atmospheric pressure being conf stantly maintained above the rack piston 16.

casing for a flexible tube 22'which at its outer end is provided With a 'check valve indicated at 23, and a cut 'oi valve 24, and which at its inner v end extends into the lower portion of the outer cylinder 5 and communicates at the point 25 with the interior of a valve cup 26 which is secured to the bottom 6 of the cylinder 5. Air from an air pump may be forced through the tubing 22 to the valve cup, the check valve: 23 which is constructed similar to the ordinary tire valve, allowing movement of the air from the pump into the tube, and of course preventing the air from rushing back from the tube of the'pump.

The cut offivalve 24, which is a three-way; f valve, is,

when the air' is to be introduced in the cylinder, moved to the position indicated in Figure 4,` in which'it will be noted that a short passage from the valve 23 to the tube exists.- When air' is to be exhausted from the jack in order to allow the latter to collapse, the valve 24 will be `moved from the position indicated in Figure '-3 to` that indicated'in Figure 2, in which'it will be seen thatl ay assage will thusl besprovided from the tu 22 to an exhaust' port 27. The position of is that taken when the -j ack has been raised to the desired height, and it, is desired to cut olf quickly the flo-w of air from the pump tothe Jack.. vIn this instance, the air will have. a free passage from the check valve 23 to the-'exhaust port 27, which will not reach Athe tube 22. Thus the height to which the'. jack may be raised can be quickly controlled.

The automatic valve for controlling the flow of air to the linn includes a cylinder' 28 extending through the f washerl 11 to the piston 10', and threaded into d said piston, said cylinder havin a reduced valveand forms a snug upper extension 29 provided with a" port 3() communicating through a passage 31. formed in ythe central thickened portion 32 of the piston, with the interior of the inner-cylinder 9 below the rack piston 16. d

The lower portion of the Itube 28 of the valvefis tapered as at 33 to snugly lit, when the-jack is in collapsed position into the 'valvecup 26, which is tapered to 'snugly recelve the lower end 33 l washer 34 seated in the' base of the cupr of the valve.

26 around the opening 25 through which the air 'enters the cup, snugly receives the lower ends of the tapered portion 33 of the jointtherew'th.t

.Slidably arranged in the tube or clyilinder `28 of the valve, is a piston 35 having a dependlng annular skirt 36; the piston thus the valve shown in Figure 3,

r and outer cylinders,

being in the shape of an inverted cup. rl`his piston when in.. lowered position, closes the ports 37 cut in the lower portion 33 of the valve cylinder, and through which, when the piston is raised, air may enter the outer cylinder beneath the cylinder piston 10.

`Bleed holes 38l provided in the piston, preceiving a spring 41 which at its` lower end, S0y

rests against the piston-35 and at its upper end rests against the upper closed end 42 of the extension 29. The spring 41nor ma-lly tends to maintain the'p-iston 35 of the valve in lowered rposition, that is, in the S5 position indicatedy in Figure 5.

.A port-43 provided centrally of the piston 35,J communicates with the tube, 40, and

hence establishes cognmunication from the air inlet port 25 upwardly through the pis- 90 ton 35,.tube 40,.reduced extension 29, port 30, channel 31, to the interior of the cylinder 9. A f

It will be noted atthis point'that the area o f the valve piston 35, exposed to in-coming alr is much greater than the surface exposed to the pressure which may be built up in the cylinder 9, this fact being apparent when it is noted that the area ofthe upper surfaze exposed to the pressure'from the cylinder 9 10o is equal to the interior diameter of thel piston tube 40, while the area of the piston exposed to the in-coming air is equal to the interior diameter of the ski11t-36 'of the piston.

- The ,operation of the valve may be de- 105 scribed as follows; Assuming thatthe Arack 4is collapsed within the cylinder 9 and the cylinder 9 in turnvcollapsed within the cylinl der 5, the lautomatic valve will .be seated within the cup y26 and the parts will be in l'le position' indicated in Figure v5. -Air now admitted. from the tube 22 through theinlet port 25 will pass ,up through the port 43 of4 i I the piston 35, through the tube 40, port 30, 5

and thenceto the cylinder 9 below the rack '115 piston 1-6. `As the pressure isbuilt up Within\ i the cylinder, the rackpisto'n will be raised,-

-thus extending the rack, and consequently moving the head 18 of the jack upwardly to- Ward the work. g So far, only enough airV pressure has been built upf-in the cylinder 9 t0 overc me weightof the rack.`v As soon as the headv of the rack feng-ages the work,

or as soonl as thepiston 16 engages the partition 14Iin limitlng the outwardmovement l1254 of the rack, the pressure built up in the cylinder 9 will increase. As the air is rontinued to be'pum Jed, pressure on the outside or lower sur ace of the piston 35, will 'l gradually overcome the pressure within the L30 Maasai ing the piston 35 and shifting the tube 40 upwardly to cut off the port 30, andraising the skirts of, the valve in order to uncover the-ports 37. This upward movement of the piston will oocur at a point after the pressurel within the cylinder 9 and the inflowing air current is equ-alized 4or counterbalanced, suoli` movement occurring when additional pressure sullioient to overcome tension of the spring 41 is applied to the lunderface of the valve.

The valve having now moved from the position shown in Figure 5 to that shown in Figure 6 and the ports 37 having been uncovered, the air will now enter the outer cylinder through the ports 37 below the piston 10, and as the air is continued to be forced into the outer cylinder, this piston carrying with it the valvewill rise off of the seat 26 and will move bodily upward until the incoming current of air has been cut olf.

As the piston 1() moves upwardly, the inner cylinder 9 which is fixed to the piston will be shifted outwardly, and of course will carry with it therack l15, together with the head 18,\thus raising the latter into engagement with the work and lifting the-work the desired amount-or until the air controlling valve 24 in the Hexible tube 22 has been moved into the cut-o1 position `inidcated in Figure 3.` f y When the jack`is to be put away, the cut of Valve 24 will be shifted into the position indicated in Figure 2, and ythefaction of gravity causes the exhaustof .air from the outer cylinder 5-below the piston 10, out

from the pipe 22 to the atmosphere, thus allowing the piston 10 to move downwardly,

and subsequently to exhaust the air from below the piston, which exhaust will relieve the pressure below the valve piston 35.

The spring '41 will move theI valve i down, thus opening the port 30 and allowing the exhaust of air from the cylinder 9, thus allowing the rack to be moved by gravity down into the cylinder. `As the piston 10 moves down in the normal position, the valve will again be seated in the cup 26, so that `air exhausting lfrom the cylinder 9 will pass out through the tube 22 to the atmos-- phere, and will be prevented from finding access to the space in the outer cylinder be' low the piston 10.

' lt will thus b e seen that byattaching a pump to the pipe Y22, and turning the stop- 'cock 24 to any operativefposition, allowing the air toflow into the jack,will cause the extension ofthe jack into position to engage and lift lthe work, 'andthat when it is i desired to disengage `the jack, all that it is necessary to do is to turn the stop-cock tov the position for opening the port 27, the

`gravity acting upon the parts of the jack will'cause vthe expulsion of the air. The

.action-of the-piston will automatically altomatically allow the exhaust of the air from the outer and inner cylinders in proper order.

Arranged at the upper portion of the inner cylinder 9 is the mechanism for automatically controlling the rack 15. cludes a dog'44 pivotally mounted on pin 45 arranged above thepartition 14. `Fixed to vthe dog and movable therewith is an arm 46 extending alongside the rack 15. This arm has an offset outer end 47 which rests upon the upper ends of a spring 48 arranged in av socket 49 lsupported on one wall of the cylinder 9 above the partition 14'. The spring tends to holdthe arm 4'6 in raised position, and consequently hold the dogs out of engagement with the teeth of the rack, as shown in Figure 8.

Mounted on a pin or other suitable support 50 carried on the wall ofthe cylinder,

is a bell cra-nk lever 51, one arm of which is lug 54 carriedby the head of the rack, en-y gages the arm of the lever 51' towhich the spring is connected, yand moves this arm about the pivot 50 until the spring is passed just below the pivot point 50, when 1t will be stopped by engagement with the lug 53` of the arm 46. The position of the parts as thus described, is shown in Figure 9, and it will be noted that the spring 52 will in this position bring the nose of the dog just inside the edges ofthe teeth in such position that when the rack is moved upwardly, the nose of the dog will ride over the outer tips of the teeth of the rack. T he arm 46 of the dog now holds the spring 48 slightly compressed. i

As the rack movesy upwardly when air is admitted into the jack, the nose of the dog `rides over the'teeth'of theV rack until the head 18 of the ja'ck engages and receives the full weight of the load. When this happens the rack will tend to shift downwardly. This will cause the dog 44 to be moved into full engagement witlr the teeth of the rack,

-due to the fact that the upper face ofthe nose of the dog'is cam-shaped as at 55, andithis movement ,of the dog into full engagement withthe teeth will'shift the arm 46. down', thus compressing the spring 48, and also, engaging the lug 53 against the free arm of the lever 5l and shifting this lelt inl ist its

ver back upon its pivot 50 until the springY 52 is moved upwardly beyond the pivota point. The parts in this position are shown in Figure 10. N ow it will be seen that when the load is removed from the head of the jack as the jack is collapsed, the spring 48 in expanding will throw the arm 46 upwardly, thus fully disengaging the dog-14 from the teeth of the rack.

The rack can now move downwardly under the action of gravity, unhampered by any'engagement 'with the dog.` As it moves downwardly and settles into nested. position, the lug 54 will again engage the upper arm of the bell crank lever, thus 'shifting it into the position indicated in Figure 9, and again drawing the dog into such .position that the tips of the teeth of the rack will be engaged by the nose of the dog. lt will thus be seen that the action of the dog in supporting the rack when the latter is under load, and in releasing the rack so asf to be nested` is entirely automatic.

Although l have described the preferred embodiment rof my invention, l may desire to make such changes in the construction, combination and arrangement of lparts thereof as do not depart from the spirit of the invention or the scope of the appended claims.

l claim: i

l. A jack .including an outer cylinder, an inner cylinder mounted in the outer cylinder and having a piston and engaging the said outer cylinder, a rack arranged slidably in the inner cylinder and having a piston engaging thefinner cylinder, means for admitting air to the outer cylinder, below the piston `carried by the inner cylinder, and valve meansP for directing the air first into the inner cylinder for raising the rack,

and then int'o the outer cylinder for raising the inner cylinder, said valve operating when the outer cylinder is opened tothe. atmosphere to allow exhaust of the air first from the outer cylinderI` and. then from' the inner cylinder, substantially as described.

A2. A pneumatic jack includilg an outer cylinder, a cylinderpiston arr nged therein, an inner cylinder connected to the cylinder piston for movement therewith, and capable of longitudinal movement relatively to the outer cylinder, a piston slidable in the innencylinder and vhaving means for engaging the work, means for permitting ya` pressure fluid to the outer cylinder below the cylinder piston, said means being operable for opening the outer cylinder to the atmosphere at will, and a valve arranged 1n the cylinder piston and incorporating automatic operating means for admitting the pressure and iiuid first to the inner cylinder and then to the outer cylinder, for expand` ing the 'ack, said valve means operating to' allow ex aust of the pressure duid from the .wo-rk, and a valve carried `by Menem cylinders, when the outer cylinder is opened to the, atmosphere, forl allowing the col- I a reducedl tubular portion provided with a port leading to the inner cylinder, a valve piston arranged within the valve cylinder, and having an opening provided therein, said piston being provided with a sleeve slidable within the reduced portion of the valve cylinder, and a .spring maintaining the valve in position for closingthe ports of the valve cylinder which connect with I the outer cylinder and for opening the port of the inner cylinder when the jack is in collapsed position, said valve having a. lesser area exposed to the inner cylinder than to the cup, substantially as described.

v.4. A jack including an outer cylinder, means for admitting a pressure fluid to thc outer cylinder including a valve cup iixed with relation to the outer cylinder, a cylinder piston movable in the outer cylinder, an ,inner cylinder yfixed to the cylinder piston, a piston arranged within the inner cylinder, and carrying means for engaging the the cylinder piston and including means cooperating 'with the valve cup for preventing communicating between the cup and the outer cylinder prior to the movement of the cylinder piston to extended position, said valve including communicating ports to the outer cylinder and a communicating port to the inner cylinder, and' including aspring pressed piston which closes the communicating ports to the outer cylinder and opens the communicating ports to. the inner cylinder when the jack is in collapsed position, and is capable of movement to close the port-of the inner cylinder and open the ports of the outer cylinder, said piston having a ylarger area exposed to the cup than tothe v and cooperating with the inlet means for admitting air to the inner cylinder and then to the outer cylinder in expanding the jack and for allowing the expulsion of air from the outer cylinder and then from the inner cylinder from the jack, substantially as described.

6. A pneumatic jack including an outer cylinder, an inner cylinder slid'able in the outer cylinder, and having a piston engaging the outerylinder, a member including a piston sliding lwithin the inner cylinder, a fluid inlet and exhaust means, and a valve carried by the cylinder piston and cooperating with the fluid inlet and exhaust means for admitting fluid to the inner cylinder and then to the outer cylinder and expanding the jack, and for allowing exhaust of Huid from the outer cylinder and from the inner 'cylinder when the jackis in collapsed position.

7. A jack including an inner and outer cylinder with one cylinder slidable with respect to the other, a piston movable in the inner cylinder, a piston movable in the outer cylinder, the piston arranged within'the -inner `cylinder carrying a lifting member, and a fluid inlet and exhaust `means, an automatically operating valve for controllingl the fluid inlet` and exhaust means for admitting fluid t-oJ the inner and outer cylinders for extending the jack, and for exhausting the 4fluid from the outer and inner cylinders when the jack is in :collapsed position, and

' means in the inner cylinder automatically operated for controlling the position of the jack.

8. `ranged in the cylinder, and movable into raised and lower positions relatively thereto, a dog pivoted in the cylinder and having an arm extending alongside the rack, a bell crank lever pivoted to the cylinder, a. spring connecting one arm of the bell crank lever with the dog for bringing the nose of the dog into slight Aengagement with the te( th of the rack when the spring controlled arm of the lever is depressed, a spring supported by the cylinder normally engaging vthe dog arm for tending to hold the dog out-of engagement with the teeth of the rack, means on the rack for engaging the spring arm'of the lever for moving the dog into slight engagement with the teeth when the rack is in lowered position, said "dog being movable when load is applied to the rack, by coop- A jackincluding acylinder, a rack areration of the nose of the dog and the teeth of the rack into full engagement with the rack, and a lug carried by the dog arm and vengageable against the free end of the bell crank lever when weight is placed upon the 2 U rack, for moving the bell crank lever into a position whereby the dog will be sprung out of engagement with the rack teeth by the spring normally in engagement with the xllog1 arm when the rack is relieved ofthe raised and lowered position, a pivoted dog, a bell crank lever mounted on a xed independent pivot and having a spring'connec- 9. A jack including a rack movable in to tion with the dog Ifor moving the nose of.

the dog into slight engagementwith the teeth of the rack when the bell crank lever is depressed, means for' depressing the bell crank lever when the rack is in lowered position, spring actuated means normally tending to hold the dog out of engagement with the teeth 'of the rack, said dog being movable Lby the rack `teeth into full engagement with the rack teeth when the load is placed upon the rack, and means for engaging the bell crank lever and moving it into raised position, when the'load is placed upon the rack, whereby when the rack is relieved of the load, the spring actuated means may operate to throw the dog outof engagement 'withthe teeth of the rack.

10. A jack includingv a rack movable. into raised and lowered position, meansor actuating the rack, automatic means cooperat-v ing with the rack for retaining the rack inv raised position against the tensionv of a load,

said automatic means becoming active for releasing the rack and operable independently of the actuating means for said rack when said rack is relieved of said load whereby to allow movement of the rack into lowered po'sition. A

11. A jack including a rack movable. into raised and lowered position, means for actuating the rack, means cooperating with the rack for sustainingl the latter in raised position under the weight of a load, and means automatically operable independently of the actuating means for the rack for releasing the sustaining means to permit the rack to lower when the actuating means for the rack has been released and the rack has been relieved of the load.

\ 5N I 1f Y WILLl KELLY. 

